Author Topic: TM32 jetting Compromise  (Read 2700 times)

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strat71

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on: September 16, 2017, 09:21:15 pm
hi
always trying to find the best jetting for my 2003 bullet...
the configuration is: short bottle, TM32 with Ace canister.

the best setting for the pilot jet is 25 and 1-3/4 turns out on the air screw... starts easily, even cold..

i had to use shims on the (P4 jet) needle because the 3rd position from the bottom is too cold and 2nd from the bottom is too rich...
so the best position i found is 2.75 (2nd position plus a 3/4 shims), great pull, nice brown plug.

But... they don't work well together... when i have 25 pilot jet and 2.75 needle positon, i have a hole just after the idle throttle position before the needle comes into action... not a big deal but annoying when rev slowly with a low throttle...

i tried to enrich the needle position, 2.5 needle position and 2.25 needle position, the hole disapears at 2.25 but i'm too rich, black and suity plug...
 
i also tried to put a 27.5 pilot jet but the screw is a little off at 2.5 turns out... and now starting the engine cold is not easy... it takes a douzain kicks often helped with electric start...

i kept this last try... the only drawback is to cold start...
 
any other idea?? throttle valve cutaway? mine is stock...
are they available??
Ben
 
« Last Edit: September 17, 2017, 11:00:30 pm by strat71 »


longstrokeclassic

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Reply #1 on: September 16, 2017, 10:29:27 pm
By making over-adjustments either side of it, it does sound as if your trying to compensate for an incorrect slide cutaway.
There should be a number on it so you know where you're starting from.
Might be best to seek expert advice from a Mikuni guy as to how far from stock you need to go to solve the problem you're describing.


ace.cafe

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Reply #2 on: September 17, 2017, 01:50:00 am
Have you tried a P6 needle jet?

The needle position has only a very small effect at the throttle position you described. Small throttle opening is almost entirely governed by the needle jet.

Regarding the slide cutaway, there is only one slide available for the TM32. It is a flat slide.
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strat71

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Reply #3 on: September 17, 2017, 08:15:57 am
Thanks Ace,
sounds like a thing to try... P6 needle, i guess i'll have to lean the needle position...
will report if i find a sweet spot...
Ben


tooseevee

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Reply #4 on: September 17, 2017, 05:05:20 pm
hi
always trying to find the best jetting for my 2003 bullet...
the configuration is: short bottle, TM32 with Ace canister.

i also tried to put a 2.75 pilot jet but the screw is a little off at 2.5 turns out... and now starting the engine cold is not easy... it takes a douzain kicks often helped with electric start...

Ben
 

            I only comment because this subject interests me. I, too, have chased a cold kick start problem for three years. I've probably been inside my TM32 as many times as you have. I see flow circuits in my sleep.

             I think you meant 27.5 pilot jet above not 2.75.

             Sorry I can't give you any hints because my engine and setup are totally different. For me, the 27.5 always ended up being the right pilot.

              Good luck.
RI USA '08 Black AVL Classic.9.8:1 ACEhead/manifold/canister. TM32/Open bottle/hot tube removed. Pertronix Coil. Fed mandates removed. Gr.TCI. Bobber seat. Battery in right side case. Decomp&all doodads removed. '30s Lucas taillight/7" visored headlight. Much blackout & wire/electrical upgrades.


Blltrdr

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Reply #5 on: September 17, 2017, 06:45:52 pm
            I only comment because this subject interests me. I, too, have chased a cold kick start problem for three years. I've probably been inside my TM32 as many times as you have. I see flow circuits in my sleep.

             I think you meant 27.5 pilot jet above not 2.75.

             Sorry I can't give you any hints because my engine and setup are totally different. For me, the 27.5 always ended up being the right pilot.

              Good luck.

Read his comment again. He states he's using a 25 pilot jet and is shimming his needle position 3/4.
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tooseevee

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Reply #6 on: September 17, 2017, 09:38:13 pm
Read his comment again. He states he's using a 25 pilot jet and is shimming his needle position 3/4.

            Yes, I know that. I'm not disputing that.

            I was only correcting the one typo in the sentence in his original post where he says "I also tried to put a 2.75 pilot jet but the screw is a little off at 2.5 turns out...".

            Look again - you'll see it 
RI USA '08 Black AVL Classic.9.8:1 ACEhead/manifold/canister. TM32/Open bottle/hot tube removed. Pertronix Coil. Fed mandates removed. Gr.TCI. Bobber seat. Battery in right side case. Decomp&all doodads removed. '30s Lucas taillight/7" visored headlight. Much blackout & wire/electrical upgrades.


strat71

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Reply #7 on: September 17, 2017, 11:05:06 pm
right, sorry it was typo.. i corrected the original post, sorry it's been confusing...

anyway...
i found something yesterday by looking at the needle jet option, there seems to be two types of jets, one is for 2 strokes (primary type) and one for 4 strokes (bleeding type).. if i read correctly...

it turns that i have the primary type on my TM32, i'm not quite sure if i understood the comments on the differences, but the hole just after idle may be caused by the use of the wrong type of jet...
i'm gonna try the bleeding one and report...
(edited cant' find a source for a bleeding type P4 jet for TM32) i may not try...

subsidiary question: is a bleeding type P4 is the equivalent for a primary type P4??? i mean if i got a primary P4, will a bleeding P4 will be adapted to my carburation?? or should i go leaner or richer??

let me know if you have some comments...
Ben
« Last Edit: September 19, 2017, 12:22:05 am by strat71 »